微視的核構造反応模型を用いた 9 Li 原子核の励起状態の研究

RCNP研究会「核子・ハイペロン多体系におけるクラスター現象」RCNP研究会「核子・ハイペロン多体系におけるクラスター現象」 (7月26,27日, 2013 at関東学院大学KGU関内メディアセンター) 微視的核構造反応模型を用いた9Li 原子核の励起状態の研究古本　猛憲 (一関工業高等専門学校) 共同研究者須原唯広 (松江工業高等専門学校) 板垣直之 (京都大学基礎物理学研究所)

Contents • Motivation • - The 9Li nucleus has a role of the core in 11Li • - Structures of the 9Li nucleus • Formalism • - Stochastic Multi-configuration mixing Method • - Microscopic Coupled Channel (MCC) Method • with complex G-matrix interaction (CEG07) • Results • - Elastic & Inelastic cross sections • - Discussion for the second 3/2- state • Summary

Motivation Halo structure 7Be + p 8B 9B 10B 11B 12B 13B 10Be + n Z=5 7Be 9Be 10Be 11Be 12Be Z=4 7Li 8Li 9Li 6Li 11Li Z=3 4He 6He 8He 9Li + n + n Z=2 4He + n + n N=2 N=3 N=4 N=5 N=6 N=7 N=8 Experiment I. Tanihata et. al., (Phys. Rev. Lett. 55 (1985) 2676) T. Minamisono et. al., (Phys. Rev. Lett. 69 (1992) 2058) I. Tanihata, (J. Phys. G: Nucl. Part. Phys. 22 (1996) 157)

Motivation Break up of 11Be → 10Be + n Importance role of the core excitation for the nuclear reaction 8B elastic scattering 11Li has a halo structure 9Li itself in this study K. Horii et. al., (Phys. Rev. C.81 (2010) 061602(R)) A. M. Moro et. al., (Phys. Rev. C.85 (2012) 054613)

Formalism (Structure) Z Brink model + Stochastic multi-configuration mixing Randomly fixed 9Li n1 n2 t Hamiltonian α Central : Volkov No.2 (W=1-M, M=0.6, B=H=0.08) LS : G3RS (VLS=2000MeV) Effective NN interaction

Energies & rms radii & B(E2) [7] No-core shell model [8] TOSM + UCOM [9] α + t + n + n [11] 6He + t B(E2; 1/2- → 3/2-) Exp. 6.8(3) e2fm4 Cal. 8.778 e2fm4 T. Furumoto, T. Suhara, and N. Itagaki (Phys. Rev. C.87 (2013) 064320)

Transition density transition density CEG07 Formalism (Reaction) Microscopic Coupled Channel (MCC) The diagonal and coupling potentials are derived from microscopic view point. vNN(s) r2 r1 R Projectile Target

Quasi-elastic 9Li + 12C cross section In MCC with CEG07 to reproduce the data T. Furumoto, T. Suhara, and N. Itagaki (Phys. Rev. C.87 (2013) 064320)

Elastic & Inelastic cross sections T. Furumoto, T. Suhara, and N. Itagaki (Phys. Rev. C.87 (2013) 064320)

Decomposition into monopole & quadrupole transitions Monopole Quadrupole T. Furumoto, T. Suhara, and N. Itagaki (Phys. Rev. C.87 (2013) 064320)

Mutual-excitation and multistep effects ✔Mutual-excitation (12C*) effect Minor role for all 3/2- states ✔Multistep (9Li*) effect Drastic change of the 3/22- state Minor role for other 3/2- states T. Furumoto, T. Suhara, and N. Itagaki (Phys. Rev. C.87 (2013) 064320)

Second 3/2- state shows exotic behavior in the inelastic angular distribution Need for the investigation of the state in detail

Decomposition into K-quantum number Z 9Li n1 n2 t K = 1/2 only K = 3/2 only α T. Furumoto, T. Suhara, and N. Itagaki (Phys. Rev. C.87 (2013) 064320)

Deformation of 9Li Exp. -2.53(9) efm2 In the collective model K = 1/2 only K = 3/2 only In the assumption, all Q0 gives positive values Prolate like deformation T. Furumoto, T. Suhara, and N. Itagaki (Phys. Rev. C.87 (2013) 064320)

Behavior of two valence neutrons in 9Li α+ t + di-neutron α+ α + di-neutron 10Be 9Li T. Furumoto, T. Suhara, and N. Itagaki (Phys. Rev. C.87 (2013) 064320) n n n n t α α α Analogy

Multi-step effect T. Furumoto, T. Suhara, and N. Itagaki (Phys. Rev. C.87 (2013) 064320)

Summary • Application of microscopic cluster and microscopic folding modes to 9Li nuclear scatterings • Inelastic cross section to the 3/2- state • - Quadrupole transition for the 2nd 3/2- state • - Monopole transition for the 3rd and 4th 3/2- states • Possibility in the 2nd 3/2-state • - triaxial deformation & mixing of di-neutron components • The multi-step coupling effect • - important for the 2nd 3/2- state • - through the 1st 1/2- and 5/2- states

微視的 核 構造反応模型を用いた 9 Li 原子核の励起状態の研究